Electromagnetic switch

ABSTRACT

An electromagnetic switch is provided which includes: a coil generating magnetomotive force; a frame accommodating the coil and generating a flux path; a resin cover covering an opening of the frame; and a current-supply terminal member energizing the coil. The current-supply terminal member includes: a blade-shaped terminal whose end is connected to the coil and whose another end is drawn out of the resin cover in the axial direction of the electromagnetic switch; and a plate-shaped external connection terminal whose end is joined to an end of the blade-shaped terminal and whose another end is drawn out in the direction intersecting the axial direction. A portion between the ends of the external connection terminal is insert-molded in a terminal anchor block provided with the resin cover. A female terminal of a power supply connector provided at an electric supply line is fitted and electrically connected to the external connection terminal.

CROSS-REFERENCE TO RELATED APPLICATION

This is a Division of application Ser. No. 13/158,985 filed on Jun. 13,2011, which claims the benefit of priority from earlier Japanese PatentApplication No. 2010-134394 filed Jun. 11, 2010, the description ofwhich is incorporated herein by reference.

BACKGROUND

(Technical Field)

The present invention relates to an electromagnetic switch includingexcitation coils that generate magnetomotive force when current ispassed therethrough, and current-supply terminal members that supplycurrent to the excitation coils upon reception of electric power from anexternal power supply.

(Related Art)

Electromagnetic switches are well known in which a plunger is driven bythe attractive force of an electromagnet so that electrical contacts areopened/closed in synchronization with the movement of the plunger.

Such an electromagnetic switch uses a process in which current ispassed, via current-supply terminal members, through excitation coilsincorporated in a switch frame to allow the excitation coils to generatemagnetomotive force by which the plunger is driven. Metal terminalplates, which are generally called blade-shaped terminals, are mostfrequently used as the current-supply terminal members for supplyingcurrent to the excitation coils. As disclosed in JP-A-2009-191843, forexample, blade-shaped terminals each have one end which is directly orindirectly connected to an excitation coil in the electromagneticswitch, and the other end which is drawn out in the axial direction ofthe electromagnetic switch from inside and through a resin cover thatcovers an opening of the switch frame.

According to the terminal structure mentioned above, wiring work for theelectromagnetic switch is facilitated. Specifically, in the wiring work,electric supply lines from outside are connected to the respectiveblade-shaped terminals. The connection is established by only directlyfitting a power supply connector provided at the ends of the electricsupply lines to the ends of the blade-shaped terminals (the ends of theblade-shaped terminals, which are drawn out of the resin cover).

Also, recently, a waterproof terminal structure is under development forthe purpose of enhancing reliability of electromagnetic switches. FIG. 7is a general side elevational view illustrating a starter installing anelectromagnetic switch of conventional art. The electromagnetic switchshown in FIG. 7 has the terminal structure mentioned above and includesa resin cover 9, a power supply connector 23, and a connector fittingmember 20 a to be fitted to the power supply connector 23. In order toenhance waterproofing properties, the connector fitting member 20 a isprovided around the blade-shaped terminals, being integrated into theresin cover 9, while a piece of waterproof rubber, for example, issandwiched between the connector fitting member 20 a and the powersupply connector 23. Owing to this terminal structure, anelectromagnetic switch having good reliability is produced at low cost.

An electromagnetic switch may be installed in a vehicle starter andarranged in an engine compartment. In an increasing number of cases,however, the installation space in an engine compartment is restricted.This is because on-vehicle devices, such as engine accessories, areincreasingly used recently and thus the interior of the enginecompartment is crowded with these devices. In particular, in many cases,spatial constraints are imposed on an electromagnetic switch in itsaxial direction, when the engine in use is a transverse engine, or asmall-displacement engine having a small number of cylinders.

Further, an electromagnetic switch to be installed in a vehicle startermay have the terminal structure as mentioned above, i.e. may useblade-shaped terminals that are metal terminal plates with the endsdrawn out from inside and through a resin cover in the axial directionof the electromagnetic switch. When such an electromagnetic switch isused, the length of the axial projection in the terminal structure willadd constraints to the installation of the switch, the axial projectionincluding a power supply connector to be fitted to the ends of theblade-shaped terminals.

SUMMARY

An embodiment provides a terminal structure in an electromagnetic switchhaving blade-shaped terminals axially drawn out from inside and througha resin cover, the blade-shaped terminals each being used as a part of acurrent-supply terminal member, and the terminal structure being able toreduce the length of its axial projection that would add constraints tothe installation of the switch.

As an aspect of the embodiment, an electromagnetic switch is providedwhich includes: an excitation coil which generates magnetomotive forcewhen current is passed therethrough; a switch frame which accommodatesthe excitation coil and generates a flux path allowing magnetic fluxgenerated by the magnetomotive force of the excitation coil to passtherethrough; a resin cover which is assembled into the switch frame tocover an opening on one end side of the switch frame; and at least onecurrent-supply terminal member which receives power via an electricsupply line and energizes the excitation coil, wherein thecurrent-supply terminal member includes: a blade-shaped terminal whoseend on one side is directly or indirectly connected to the excitationcoil and whose end on the other side is drawn out of the resin coverthrough the resin cover in the axial direction of the electromagneticswitch; and a plate-shaped external connection terminal whose end on oneside is electrically and mechanically joined to an end on the other sideof the blade-shaped terminal and whose end on the other side is drawnout in the direction intersecting the axial direction of theelectromagnetic switch, a portion between the ends of the externalconnection terminal being insert-molded in a terminal anchor block whichis integrally provided with the resin cover, and a female terminal of apower supply connector provided at an end of the electric supply line isfitted to and electrically connected to the end on the other side of theexternal connection terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a plan view, including a partial cross section, illustrating aresin cover of an electromagnetic switch, as viewed from an axial rearend of the cover, according to a first embodiment of the presentinvention;

FIG. 2 is a side elevational view taken along a line A-A of FIG. 1,including a partial cross section, illustrating the electromagneticswitch as viewed from the side of the resin cover;

FIG. 3 is a perspective view illustrating a terminal structure of theelectromagnetic switch as viewed from the side of the resin cover;

FIG. 4 is a perspective view illustrating a cap used in theelectromagnetic switch;

FIG. 5 is an electrical circuit diagram illustrating a starterinstalling the electromagnetic switch;

FIG. 6 is a general side elevational view of a starter installing theelectromagnetic switch;

FIG. 7 is a general side elevational view of a starter installing anelectromagnetic switch according to a conventional art; and

FIG. 8 is a perspective view illustrating a terminal structure of anelectromagnetic switch as viewed from the side of a resin cover,according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the accompanying drawings, hereinafter will bedescribed some embodiments of the present invention.

First Embodiment

Referring to FIGS. 1 to 6, a first embodiment of the present inventionis described. FIG. 6 is a general side elevational view of a starter 2installing an electromagnetic switch 1 of the first embodiment.

The starter 2 has a well-known function. Specifically, the starter 2includes the electromagnetic switch 1, a pinion 3, a motor 5 and abattery 10 (see FIG. 5). The starter 2 has a well-known function ofbringing the pinion 3 into engagement with a ring gear 4 (also see FIG.5) of an engine to transmit torque of the motor 5 from the pinion 3 tothe ring gear 4. The ring gear 4 is rotated by the transmitted torquefor the start of the engine.

The electromagnetic switch 1 includes a switch frame 6 (see FIG. 2),first and second excitation coils 7 and 8 (see FIG. 5), a resin cover 9,first and second current-supply terminal members (described later),first and second plungers 11 and 12 (see FIG. 5), and a shift lever 13(see FIG. 5). The switch frame 6 has a bottomed cylindrical shape. Thefirst and second excitation coils 7 and 8 are accommodated in the switchframe 6. The resin cover 9 is assembled into the switch frame 6 to coveran opening on one end side of the switch frame 6. The first and secondcurrent-supply terminal members receive supply of electric power fromthe battery 10 (see FIG. 5) to supply current to the first and secondexcitation coils 7 and 8, respectively.

The switch frame 6 is made of iron, for example, and also serves as ayoke that allows magnetic flux to pass therethrough, the magnetic fluxbeing caused by the magnetomotive force of the first and secondexcitation coils 7 and 8.

The first and second excitation coils 7 and 8 are connected in series inthe axial direction (left and right directions as viewed in FIG. 6) ofthe electromagnetic switch 1. Being supplied with current from the firstand second current-supply terminal members, the first and secondexcitation coils 7 and 8 form electromagnets to drive the first andsecond plungers 11 and 12, respectively, in conformity with theelectromotive force of the electromagnets.

The first plunger 11 is arranged so as to be axially movable along theinner periphery of the first excitation coil 7. When the first plunger11 is moved being driven by the electromagnet, the pinion 3 is pushedtoward the ring gear 4 via the shift lever 13 (see FIG. 5).

The second plunger 12 is arranged so as to be axially movable along theinner periphery of the second excitation coil 8. Electrical contacts(described later) provided at a power supply circuit of the motor 5 areopened/closed in synchronization with the movement of the second plunger12.

The resin cover 9 has a bottomed cylindrical shape and has a cylindricalbody 9 a. The cylindrical body 9 a has an outer periphery along which astep portion is formed. As shown in FIG. 2, the cylindrical body 9 a hasan end inserted into the inside of an opening of the switch frame 6 forassemblage into the switch frame 6. In the assemblage, an end portion ofthe opening of the switch frame 6 is crimped onto the step portion ofthe cylindrical body 9 a for fixation to the switch frame 6 (see FIGS. 1and 3).

As shown in FIG. 3, the resin cover 9 is provided with a bolt-shapedbattery terminal 14 and a bolt-shaped motor terminal 15, each having anouter periphery which is threaded to provide a male screw. Each of thebattery terminal 14 and the motor terminal 15 is fixed to the resincover 9 via a washer 16. The battery terminal 14 is, as shown in FIG. 5,electrically connected to a terminal of a battery cable 17 which isconnected to a positive-side terminal of the battery 10. The motorterminal 15 is electrically connected to a terminal of a motor lead 19which is connected to a positive brush 18 in the motor.

As shown in FIGS. 1 and 3, the resin cover 9 is integrally provided witha terminal anchor block 20 in the radial direction which isperpendicular to the axial direction of the electromagnetic switch 1.The terminal anchor block 20 is provided with a connector fitting member20 a which electrically connects externally provided first and secondelectric supply lines 21 and 22 to the first and second current-supplyterminal members, respectively.

As shown in FIG. 5, the first electric supply line 21 supplies electricpower to the first excitation coil 7 from the battery 10, while thesecond electric supply line 22 supplies electric power to the secondexcitation coil 8 from the battery 10. The first and second electricsupply lines 21 and 22 each have an end at which a power supplyconnector 23 (see FIG. 6) is provided for common use between the lines21 and 22. The power supply connector 23 is fitted to the connectorfitting member 20 a to electrically connect the first and secondelectric supply lines 21 and 22 to the first and second current-supplyterminal members, respectively.

The first and second electric supply lines 21 and 22 are provided withfirst and second electromagnetic relays 24 and 25, respectively. Theoperations of the first and second electromagnetic relays 24 and 25 arecontrolled by an ECU 26 that is an electronic control unit.

As shown in FIG. 5, the electrical contacts mentioned above include abattery-side fixed contact 27, a motor-side fixed contact 28 and amovable contact 29. The battery-side fixed contact 27 is integrallyprovided with the battery terminal 14. The motor-side fixed contact 28is integrally provided with the motor terminal 15. The movable contact29 faces the fixed contacts 27 and 28 and moves in the axial directionof the electromagnetic switch 1. The movable contact 29 electricallyconnects and disconnects the fixed contacts 27 and 28 in synchronizationwith the movement of the second plunger 12.

Specifically, when the movable contact 29 is brought into contact withthe fixed contacts 27 and 28, current is passed through the fixedcontacts 27 and 28 via the movable contact 29 to thereby turn theelectrical contacts to an “on” state. When the movable contact 29 isbrought out of contact with the fixed contacts 27 and 28, the currentsupply is interrupted between the fixed contacts 27 and 28 to therebyturn the electrical contacts to an “off” state. The fixed contacts 27and 28 may be provided separately from the battery terminal 14 and themotor terminal 15, respectively, and electrically and mechanicallyjoined to the battery terminal 14 and the motor terminal 15,respectively.

The first and second current-supply terminal members are each configuredby a blade-shaped terminal 30 and an external connection terminal 31,which have long-plate shapes and are made of a terminal material, suchas copper or brass. The blade-shaped terminals 30 in the first andsecond current-supply terminal members have an identical shape.Similarly, the external connection terminals 31 in the first and secondcurrent-supply terminal members have an identical shape. Therefore, thecommonality of the parts can be achieved.

In the description set forth below, the same reference “30” is used forthe blade-shaped terminals in the first and second current-supplyterminal members, and the same reference “31” is used for the externalconnection terminals in the first and second current-supply terminalmembers.

As shown in FIG. 2, the ends of the blade-shaped terminals 30 on oneside are directly or indirectly connected to the first and secondexcitation coils 7 and 8 in the interior of the resin cover 9. The endsof the blade-shaped terminals 30 on the other side are drawn out of theresin cover 9 through a slit 9 b, i.e. a through hole, in the axialdirection of the electromagnetic switch 1, the slit 9 b being formed inthe bottom of the resin cover 9. FIG. 2 exemplifies that, of the firstand second excitation coils 7 and 8, the second excitation coil 8, forexample, is connected, at its non-grounded end 8 a, to the correspondingblade-shaped terminal 30. Similarly, the first excitation coil 7 canalso be connected, at its non-grounded end, to the correspondingblade-shaped terminal 30. Specifically, the first excitation coil 7 isdisposed below the second excitation coil 8, although not shown in FIG.2. The non-grounded end of the first excitation coil 7 is permitted topass through the radial outer periphery of the second excitation coil 8,for example, and be drawn out upward in the figure for connection to thecorresponding blade-shaped terminal 30 in the same manner as indicatedin FIG. 2.

As shown in FIGS. 1, 2 and 3, each of the external connection terminals31 has a portion between the ends thereof which is insert-molded in theconnector fitting member 20 a formed at the terminal anchor block 20.The ends of the external connection terminals 31 on one side areprojected toward the center of the resin cover 9 from the back face ofthe connector fitting member 20 a and joined to the respective ends ofthe blade-shaped terminals 30 on the other side, which are drawn out ofthe resin cover 9. The ends of the external connection terminals 31 onthe other side are drawn out into the interior of the connector fittingmember 20 a.

As shown in FIG. 2, the ends of the external connection terminals 31 onone side joined to the respective blade-shaped terminals 30 drawn out ofthe resin cover 9 are each bent in the axial direction (verticaldirection as viewed in the figure) of the electromagnetic switch 1 so asto have a shape of an “L” (L shape). The L-shaped bent ends areelectrically and mechanically connected to the respective ends of theblade-shaped terminals 30 on the other side such as by resistancewelding, brazing or soldering, in a state where the respective flatsurfaces are butted against each other, or in a manner of achievingsurface-to-surface contact.

In the first and second current-supply terminal members, as shown inFIG. 2, the portions exposed outside the resin cover 9, i.e. theportions of the blade-shaped terminals 30 on the other side and theexternal connection terminals 31 on one side, the portions includingjoints between the blade-shaped terminals 30 and the external connectionterminals 31, are covered with a cap 32 which is made of resin andprovided separately from the resin cover 9. As shown in FIG. 4, the cap32 is provided with a pair of engaging claws 32 a for fixing the cap 32to the terminal anchor block 20. In fixing the cap 32 to the terminalanchor block 20, the engaging claws 32 a are engaged with the rear-facecorners of the terminal anchor block 20 so as to bridge the terminalanchor block 20 from above the front face of the terminal anchor block20 (from above the upper face of the terminal anchor block 20 having theexternal connection terminals 31 as shown in FIG. 3). It should beappreciated that FIGS. 1 and 3 illustrate a state where the cap 32 isdetached.

Hereinafter is described the operation of the starter 2.

When the first electromagnetic relay 24 is turned on by a signal fromthe ECU 26, power is supplied to the first current-supply to terminalmember from the battery 10 to energize the first excitation coil 7. As aresult, the first plunger 11 shown in FIG. 5 is attracted to theelectromagnet and moved leftward as viewed in FIG. 5. With the movementof the plunger 11, the pinion 3 is pushed via the shift lever 13 in thedirection opposite to the motor (rightward as viewed in FIG. 5).

Once the pinion 3 is brought into contact with the ring gear 4 and whenthe second electromagnetic relay 25 is turned on by a signal from theECU 26, power is supplied to the second current-supply terminal memberfrom the battery 10 to energize the second excitation coil 8. As aresult, the second plunger 12 shown in FIG. 5 is attracted to theelectromagnet and moved downward as viewed in FIG. 5. With the movementof the plunger 12, the electrical contacts provided at the power supplycircuit of the motor 5 are turned on. Then, an armature 5 a of the motor5 is energized to generate torque in the armature 5 a. The torque of thearmature 5 a is transmitted to the pinion 3. Then, when the pinion 3 isin engagement with the ring gear 4, the torque is transmitted from thepinion 3 to the ring gear 4 to crank up the engine.

The operation of the starter 2 described above is just an example, andthus the operation is not limited to this example. Let us take as anexample a vehicle installed with an idle stop system that automaticallycontrols stop and restart of the engine. In such a vehicle, the pinion 3can be engaged with the ring gear 4 when idle stop is performed butbefore the rotation of the engine is completely stopped, i.e. while thering gear 4 is still in rotation.

Specifically, for example, after performing idle stop and when theengine speed has lowered to a level which is lower than an idling enginespeed, the first electromagnetic relay 24 may be turned on to energizethe first excitation coil 7. In this case, the pinion 3 pushed in thedirection opposite to the motor is once brought into contact with anaxial end face of the ring gear 4. Since the ring gear 4 is in rotation,at the time point when the ring gear 4 is rotated to a position thatenables engagement with the pinion 3, the pinion 3 will be engaged withthe ring gear 4.

Then, when engine restarting conditions are met following the startingoperation carried out by the driver, a signal is issued from the ECU 26to turn on the second electromagnetic relay 25 for the energization ofthe second excitation coil 8. Then, the motor 5 is started to transmittorque to the pinion 3 and to thereby finally restart the engine in aprompt manner.

The first and second current-supply terminal members used for theelectromagnetic switch 1 according to the first embodiment each includethe blade-shaped terminal 30 which is fitted on through the resin cover9 in the axial direction of the electromagnetic switch 1, and theexternal connection terminal 31 which is joined to the blade-shapedterminal 30 in the outside of the resin cover 9. Accordingly, thedirection of drawing out each of the external connection terminals 31 isallowed to intersect the axial direction of the electromagnetic switch1.

In the first embodiment, the ends of the external connection terminals31 on one side, which are drawn out of the rear face of the connectorfitting member 20 a, are each bent into the shape of an “L” for joiningto the respective ends of the blade-shaped terminals 30 on the otherside drawn out of the resin cover 9. Such a joint allows the ends of theexternal connection terminals 31 on the other side to be drawn out inthe radial direction of the electromagnetic switch 1 (the directionperpendicular to the axial direction of the electromagnetic switch 1).Accordingly, the connector fitting member 20 a can be formed in theradial direction of the electromagnetic switch 1, and therefore thepower supply connector 23 provided at the ends of the first and secondelectric supply lines 21 and 22 can be fitted to the connector fittingmember 20 a from the radial direction of the electromagnetic switch 1.

Referring now to FIGS. 6 and 7, let us compare the terminal structureaccording to the first embodiment described above and the terminalstructure of a conventional art. FIG. 6 is a general side elevationalview of the starter 2 installing the electromagnetic switch 1 accordingto the first embodiment. FIG. 7 is a general side elevational view of astarter installing an electromagnetic switch according to a conventionalart. In FIG. 7, the components identical with or similar to thoseillustrated in FIG. 6 are given the same reference numerals.

In FIGS. 6 and 7, references L1 and L2 each represent an axial length inthe starter from a surface B of a starter housing 2 a, through which thestarter is attached to an engine, to an ultimate end of the power supplyconnector 23. Let us compare the axial lengths L1 and L2. As show inFIG. 7, in the terminal structure of the conventional art, the ultimateend of the power supply connector 23 is positioned outside (rightward inFIG. 7) of the axial end face of the battery terminal 14. Therefore, theaxial length L2 is larger than the axial length from the surface B forthe attachment to the engine, to the axial end face of the batteryterminal 14.

On the other hand, as indicated by the dash-dot-dot line in FIG. 6, inthe terminal structure according to the first embodiment, the ultimateend (the side face on the right side as viewed in FIG. 6) of the powersupply connector 23 is positioned inside of the axial end face of thebattery terminal 14. Therefore, the axial length L1 is made smaller thanthe axial length from the surface B for the attachment to the engine, tothe axial end face of the battery terminal 14.

Thus, the axial length L1 in the terminal structure according to thefirst embodiment described above is made smaller than the axial lengthL2 in the terminal structure of the conventional art. In this way, theinstallation properties of the starter 2 are enhanced.

In each of the first and second current-supply terminal members, an endof the blade-shaped terminal 30 on the other side drawn out of the resincover 9 and the L-shaped end of the external connection terminal 31 onone side are joined in a state where the respective flat surfaces arebutted against each other, or in a manner of achieving asurface-to-surface contact. Therefore, joint strength is well ensuredand thus reliability of the joint is enhanced, regardless of the type ofthe joint, such as a joint obtained by resistance welding, brazing orsoldering.

In the first and second current-supply terminal members, the resin cap32 entirely covers the portions exposed outside the resin cover 9, i.e.the portions of the blade-shaped terminals 30 on the other side and theexternal connection terminals 31 on one side, the portions includingjoints between the blade-shaped terminals 30 and the external connectionterminals 31. Therefore, the portions of the terminals exposed outsidethe resin cover 9 are prevented from having foreign matter attached andthus the leakage of current between two poles (between a current-supplyterminal member and another current-supply terminal member) can beprevented. Also, the cap 32 can be easily fixed to the terminal anchorblock 20 by bringing the pair of engaging claws 32 a into engagementwith the rear-face corners of the terminal anchor block 20. Therefore,the reliability of the electromagnetic switch 1 is enhanced in theendurance of insulation properties without using so many number ofassembling steps.

Further, the external connection terminals 31 each have a portionbetween the ends on one side and the other side thereof which isinsert-molded in the terminal anchor block 20. Therefore, the ends ofthe external connection terminals 31 on the other side, which are drawninto the interior of the connector fitting member 20 a, will not wobble,and thus the connection to respective female terminals of the powersupply connector 23 is reliably established.

Furthermore, since the connector fitting member 20 a is formed at theterminal anchor block 20, the external connection terminals 31 areelectrically connected to the respective female terminals by onlyfitting the connector fitting member 20 a to the power supply connector23. Thus, wiring work for the electromagnetic switch 1 can befacilitated. In addition, waterproofing properties are easily obtainedby having a piece of waterproof rubber, for example, sandwiched betweenthe connector fitting member 20 a and the power supply connector 23.Thus, a contact structure having high reliability can be provided.

Further, in the present embodiment, only the change of the resin cover 9can change the direction of drawing out the external connectionterminals 31 with respect to the circumferential direction of the resincover 9. Specifically, in changing the direction of drawing out theexternal connection terminals 31, it is not required to change the maincomponents, including the first and second excitation coils 7 and 8, ofthe electromagnetic switch 1. Specifically, in changing the direction,only the resin cover 9 has to be changed to the one suitable for thedirection of drawing out the external connection terminals 31.Therefore, the main components of an electromagnetic switch of theconventional art, except the resin cover 9, are usable in theelectromagnetic switch 1.

Second Embodiment

Referring to FIG. 8, hereinafter is described a second embodiment of thepresent invention. In the second embodiment, the components identicalwith or similar to those in the first embodiment are given the samereference numerals for the sake of omitting explanation.

In the second embodiment, an example is described in which boltterminals 33 are used at connecting portions in the first and secondelectric supply lines 21 and 22. The bolt terminals 33 refer to theterminals each having a shape of a bolt whose outer periphery isthreaded to provide a male screw, similar to the battery terminal 14 orthe motor terminal 15 as mentioned in the first embodiment.

The first and second current-supply terminal members each include theblade-shaped terminal 30 as shown in FIG. 8, a relay metal terminalplate 34 and a bolt terminal 33.

Similar to the first embodiment, the blade-shaped terminals 30 have endson one side, which are directly or indirectly connected to the first andsecond excitation coils 7 and 8 in the interior of the resin cover 9.The blade-shaped terminals 30 have ends on the other side, which aredrawn out of the resin cover 9 through the slit 9 b, i.e. a throughhole, in the axial direction of the electromagnetic switch 1, the slit 9b being formed in the bottom of the resin cover 9 (see FIG. 2).

The relay metal terminal plates 34 have ends on one side, which areelectrically and mechanically joined to the respective ends of theblade-shaped terminals 30 on the other side, which are drawn out of theresin cover 9. The relay metal terminal plates 34 have ends on the otherside, which are drawn out in the radial direction perpendicular to theaxial direction of the electromagnetic switch 1. The radially drawn outends of the relay metal terminal plates 34 on the other side are formedinto annular terminals 34 a which are electrically connected to therespective bolt terminals 33.

Each of the bolt terminals 33 has one end inserted into a fitting holeformed in the terminal 34 a of each relay metal terminal plate 34, forelectrical connection with the relay metal terminal plate 34, and theother end insert-molded in the terminal anchor block 20 integrallyprovided with the resin cover 9. The bolt terminals 33 are projectedfrom the terminal anchor block 20 in the upward direction, as viewed inFIG. 8. The portions of the bolt terminals 33 projected upward from theterminal anchor block 20 have outer peripheries fitted to respectiveannular terminals 35 (see FIG. 8) provided at the ends of the first andsecond electric supply lines 21 and 22 (see FIG. 5) to electricallyconnect the bolt terminals 33 to the first and second electric supplylines 21 and 22.

The terminal structure shown in the second embodiment uses the boltterminals 33 at the connecting portions in the first and second electricsupply lines 21 and 22. Thus, the first and second electric supply lines21 and 22 are electrically connected to the respective bolt terminals 33by fitting the annular terminals 35 to the outer peripheries of therespective bolt terminals 33, instead of establishing electricalconnection using the connector fitting (the fitting between theconnector fitting member 20 a and the power supply connector 23) as inthe first embodiment.

In this case, no installation constraints are imposed by the length ofthe axial projection of the terminal structure including the powersupply connector 23. Therefore, compared to the terminal structure ofthe conventional art in which the power supply connector 23 is axiallyfitted to the ends of the blade-shaped terminals 30 drawn out of theresin cover 9, the length of the projection in the axial direction canbe shortened, thereby enhancing the installation properties for anengine.

(Modifications)

In the first embodiment, the connector fitting member 20 a has beenformed in the terminal anchor block 20. However, in place of theconnector fitting member 20 a, a flat connector contact surface may beformed in the terminal anchor block 20, so that the ends of the externalconnection terminals 31 on the other side, which are extended in thedirection intersecting the axial direction of the electromagnetic switch1, can be projected from the connector contact surface. In this case, infitting the power supply connector 23 to the ends of the externalconnection terminals 31, an end face of the power supply connector 23 isbrought into contact with the connector contact surface formed in theterminal anchor block 20. Based on this contact, the external connectionterminals 31 are determined as being reliably in contact with therespective female terminals. Therefore, contact failure between theexternal connection terminals 31 and the female terminals can beprevented, which would have been caused such as by the insufficientfitting of the power supply connector 23.

The first and second embodiments described above have each introduced anexample of the electromagnetic switch 1 including the first and secondexcitation coils 7 and 8, and the first and second current-supplyterminal members for supplying current to the first and secondexcitation coils 7 and 8, respectively. However, the configuration ofthe present invention can also be applied to an electromagnetic switchincluding a single excitation coil and a current-supply terminal memberwith a single pole, the current-supply terminal member supplying currentto the excitation coil.

Hereinafter, aspects of the above-described embodiments will besummarized.

As an aspect of the embodiment, an electromagnetic switch is providedwhich includes: an excitation coil which generates magnetomotive forcewhen current is passed therethrough; a switch frame which accommodatesthe excitation coil and generates a flux path allowing magnetic fluxgenerated by the magnetomotive force of the excitation coil to passtherethrough; a resin cover which is assembled into the switch frame tocover an opening on one end side of the switch frame; and at least onecurrent-supply terminal member which receives power via an electricsupply line and energizes the excitation coil, wherein thecurrent-supply terminal member includes: a blade-shaped terminal whoseend on one side is directly or indirectly connected to the excitationcoil and whose end on the other side is drawn out of the resin coverthrough the resin cover in the axial direction of the electromagneticswitch; and a plate-shaped external connection terminal whose end on oneside is electrically and mechanically joined to an end on the other sideof the blade-shaped terminal and whose end on the other side is drawnout in the direction intersecting the axial direction of theelectromagnetic switch, a portion between the ends of the externalconnection terminal being insert-molded in a terminal anchor block whichis integrally provided with the resin cover, and a female terminal of apower supply connector provided at an end of the electric supply line isfitted to and electrically connected to the end on the other side of theexternal connection terminal.

The current-supply terminal members include the blade-shaped terminalswhich are fitted on through the resin cover in the axial direction ofthe electromagnetic switch, and the plate-shaped external connectionterminals electrically and mechanically joined, outside the resin cover,to the respective blade-shaped terminal. Therefore, the direction ofdrawing out the external connection terminals is permitted to intersectthe axial direction of the electromagnetic switch. For example, bydrawing out the ends of the external connection terminals in the radialdirection of the electromagnetic switch (the direction perpendicular tothe axial direction of the electromagnetic switch), the female terminalsof the power supply connector can be fitted and connected to therespective external connection terminals from the radial direction ofthe electromagnetic switch. In this case, the axial length of theterminal structure including the power supply connector is reducedcompared with the terminal structure using the blade-shaped terminals ofa conventional art. In this way, the installation properties of theelectromagnetic switch are enhanced.

In each of the external connection terminals, a portion between the endsthereof is insert-molded in the terminal anchor block which isintegrally provided with the resin cover. Therefore, the ends of theexternal connection terminals, which are extended intersecting the axialdirection of the electromagnetic switch, will not wobble, and thus theconnection with the respective female terminals of the power supplyconnector is reliably established.

Further, according to the embodiments, only the change of the resincover can change the direction of drawing out the external connectionterminals with respect to the circumferential direction of the resincover. Specifically, in changing the direction of drawing out theexternal connection terminals, the main components, including theexcitation coils, of the electromagnetic switch are not required to bechanged, but only the resin cover has to be changed to the one suitablefor the direction of drawing out the external connection terminals.Therefore, the main components of an electromagnetic switch of theconventional art, except the resin cover, are usable in theelectromagnetic switch of the embodiments. The electromagnetic switch ofthe conventional art here refers to one having a terminal structure inwhich the ends of blade-shaped terminals are drawn out to the outside inthe axial direction of the electromagnetic switch from inside andthrough a resin cover, and female terminals of a power supply connectorare connected to the respective drawn out ends of the blade-shapedterminals.

In the electromagnetic switch, the terminal anchor block is providedwith a connector fitting member which fits to the power supplyconnector.

Thus, by forming the connector fitting member at the terminal anchorblock, the power supply connector is fitted to the connector fittingmember to establish electrical connection between the externalconnection terminals and the respective female terminals. Therefore,wiring work for the electromagnetic switch is facilitated. In addition,waterproofing properties are easily obtained by having a piece ofwaterproof rubber, for example, sandwiched between the connector fittingmember and the power supply connector. Thus, a contact structure havinghigh reliability can be provided.

In the electromagnetic switch, the terminal anchor block has a connectorcontact surface with which an end face of the power supply connector isbrought into contact, and the end on the other side of the externalconnection terminal is projected from the connector contact surface.

Thus, in fitting the power supply connector to the ends of the externalconnection terminals, an end face of the power supply connector isbrought into contact with the connector contact surface formed in theterminal anchor block. Based on this contact, the external connectionterminals are determined as being reliably in contact with therespective female terminals. Therefore, contact failure between theexternal connection terminals and the female terminals can be prevented,which would have been caused such as by the insufficient fitting of thepower supply connector.

In the electromagnetic switch, one end of the external connectionterminal on one side is bent in the axial direction of theelectromagnetic switch so as to have an L shape, and the bent end isconnected to the end of the blade-shaped terminal on the other sidedrawn out of the resin cover, in a state where the bent end and the endof the blade-shaped terminal are butted against each other in thethickness direction thereof.

Thus, the ends of the blade-shaped terminals, which are drawn out of theresin cover, and the L-shaped ends of the external connection terminalsare butted against each other in the thickness direction of the terminalplates. In other words, an end of each blade-shaped terminal and an endof each external connection terminal are joined in a manner of achievinga surface-to-surface contact. With this configuration, in the event thatthe contact surfaces of the terminals are slightly displaced from eachother, good joint strength is ensured absorbing the displacement.Therefore, reliability of the joint is enhanced, regardless of the typeof the joint, such as a joint obtained by resistance welding, brazing orsoldering.

As another aspect of the embodiment, an electromagnetic switch isprovided which includes: an excitation coil which generatesmagnetomotive force when current is passed therethrough; a switch framewhich accommodates the excitation coil and generates a flux pathallowing magnetic flux generated by the magnetomotive force of theexcitation coil to pass therethrough; a resin cover which is assembledinto the switch frame to cover an opening on one end side of the switchframe; and at least one current-supply terminal member which receivespower via an electric supply line and energizes the excitation coil,wherein the current-supply terminal member includes: a blade-shapedterminal whose end on one side is directly or indirectly connected tothe excitation coil and whose end on the other side is drawn out of theresin cover through the resin cover in the axial direction of theelectromagnetic switch; a relay metal terminal plate whose end on oneside is electrically and mechanically joined to an end on the other sideof the blade-shaped terminal, and whose end on the other side is drawnout in the direction intersecting the axial direction of theelectromagnetic switch and has a fitting hole; and a bolt terminal whoseone end is inserted into the fitting hole of the relay metal terminalplate for electrical connection with the relay metal terminal plate, andwhose another end is insert-molded in the terminal anchor blockintegrally provided with the resin cover, and a portion of the boltterminal projected from the terminal anchor block has an outer peripheryfitted to an annular terminal provided at the end of the electric supplyline to electrically connect the bolt terminal to the electric supplyline.

In the current-supply terminal members of the embodiment, an end of eachof the bolt terminals is fixed to the terminal anchor block integrallyprovided with the resin cover. The bolt terminals are electricallyconnected, via the respective relay metal terminal plates, to therespective blade-shaped terminals, which are fitted on through the resincover in the axial direction of the electromagnetic switch.

In this terminal structure, unlike the connection in the conventionalart using the power supply connector as mentioned above, the annularterminals provided at the respective ends of the electric supply linesare fitted and connected to the outer peripheries of the respective boltterminals to connect the electric supply lines to the respective boltterminals. Therefore, with this terminal structure, no installationconstraints are imposed by the length of the axial projection of theterminal structure including the power supply connector. As a result,comparing with the terminal structure of the conventional art in whichthe power supply connector is fitted to the ends of the blade-shapedterminals drawn out of the resin cover, the length of the projection inthe axial direction can be shortened, thereby enhancing the installationproperties of the electromagnetic switch.

Further, in the embodiments, only the change of the resin cover canchange the attachment position of the bolt terminals with respect to thecircumferential direction of the resin cover. Specifically, in changingthe attachment position of the bolt terminals, it is not required tochange the main components, including the excitation coils, of theelectromagnetic switch, but only the resin cover has to be changed tothe one suitable for the attachment position of the bolt terminals.Therefore, main components of an electromagnetic switch of theconventional art, except the resin cover, are usable in theelectromagnetic switch of the embodiments.

The electromagnetic switch of the conventional art here refers to onehaving a terminal structure in which the ends of blade-shaped terminalsare drawn out to the outside in the axial direction of theelectromagnetic switch from inside and through a resin cover, and femaleterminals of a power supply connector are connected to the respectivedrawn out ends of the blade-shaped terminals.

In the electromagnetic switch, one end of the relay metal terminal plateon one side is bent in the axial direction of the electromagnetic switchso as to have an L shape, and the bent end is connected to the end ofthe blade-shaped terminal on the other side drawn out of the resincover, in a state where the bent end and the end of the blade-shapedterminal are butted against each other in the thickness directionthereof.

Thus, the ends of the blade-shaped terminals, which are drawn out of theresin cover, and the respective L-shaped ends of the relay metalterminal plates are butted against each other in the thickness directionof the terminal plates. In other words, an end of each blade-shapedterminal and an end of each relay metal terminal plate are joined in amanner of achieving surface-to-surface contact. With this configuration,in the event that the contact surfaces of the blade-shaped terminal andthe relay metal terminal plate are slightly displaced from each other,good joint strength is ensured absorbing the displacement. Therefore,reliability of the joint is enhanced, regardless of the type of thejoint, such as a joint obtained by resistance welding, brazing orsoldering.

In the electromagnetic switch, a plurality of the current-supplyterminal members are provided, further including a resin cap whichcovers portions of the current-supply terminal members exposed outsidethe resin cover, wherein the cap includes an engaging claw which isengaged with the terminal anchor block to fix the cap to the terminalanchor block.

For example, an electromagnetic switch installed in a vehicle starter isrestricted in the outer diameter dimension of the resin cover. What ismore, a battery terminal and a motor terminal are attached to the resincover besides current-supply terminal members. Therefore, if two or morecurrent-supply terminal members are provided, it is difficult to wellensure the creepage distance between two poles (between a current-supplyterminal member and another current-supply terminal member). If foreignmatters, for example, are attached to the portions of the current-supplyterminal members, which portions are exposed outside the resin cover,there is a concern that current leakage may be caused between the polesvia the foreign matters. Therefore, the terminals are required to beprevented from being attached with foreign matters.

From a viewpoint of preventing the increase of the number of assemblingsteps, it is desirable that the means for preventing the attachment offoreign matters to the terminals is realized as easily as possible.

In this regard, according to the embodiments, a resin cap is providedseparately from the resin cover. Using the cap, the portions exposedoutside the resin cover are covered to thereby prevent the attachment offoreign matters to the terminals. Further, the cap is provided withengaging claws which are brought into engagement with the terminalanchor block to fix the cap to the terminal anchor block.

With this configuration, the portions of the terminals exposed outsidethe resin cover are covered with the cap with easy assembling work.Therefore, the reliability of the electromagnetic switch is enhanced inthe endurance of insulation properties without using so many number ofassembling steps.

It will be appreciated that the present invention is not limited to theconfigurations described above, but any and all modifications,variations or equivalents, which may occur to those who are skilled inthe art, should be considered to fall within the scope of the presentinvention.

What is claimed is:
 1. An electromagnetic switch, comprising: anexcitation coil which generates magnetomotive force when current ispassed therethrough; a switch frame which accommodates the excitationcoil and generates a flux path allowing magnetic flux generated by themagnetomotive force of the excitation coil to pass therethrough; a resincover which is assembled into the switch frame to cover an opening onone end side of the switch frame; and at least one current-supplyterminal member which receives power via an electric supply line andenergizes the excitation coil, the current-supply terminal memberincluding: a blade-shaped terminal whose end on one side is directly orindirectly connected to the excitation coil and whose end on the otherside is drawn out of the resin cover through the resin cover in theaxial direction of the electromagnetic switch; a relay metal terminalplate whose end on one side is electrically and mechanically joined toan end on the other side of the blade-shaped terminal, and whose end onthe other side is drawn out in the direction intersecting the axialdirection of the electromagnetic switch and has a fitting hole; and abolt terminal whose one end is inserted into the fitting hole of therelay metal terminal plate for electrical connection with the relaymetal terminal plate, and whose another end is insert-molded in theterminal anchor block integrally provided with the resin cover; and aportion of the bolt terminal projected from the terminal anchor blockhas an outer periphery fitted to an annular terminal provided at the endof the electric supply line to electrically connect the bolt terminal tothe electric supply line.
 2. The electromagnetic switch according toclaim 1, wherein one end of the relay metal terminal plate on one sideis bent in the axial direction of the electromagnetic switch so as tohave an L shape, and the bent end is connected to the end of theblade-shaped terminal on the other side drawn out of the resin cover, ina state where the bent end and the end of the blade-shaped terminal arebutted against each other in the thickness direction thereof.
 3. Theelectromagnetic switch according to claim 1, wherein a plurality of thecurrent-supply terminal members are provided, further comprising a resincap which covers portions of the current-supply terminal members exposedoutside the resin cover, wherein the cap includes an engaging claw whichis engaged with the terminal anchor block to fix the cap to the terminalanchor block.